Colonies of social insects are often regarded as super organisms. Individuals are like cells and organs of a colony. As individual organisms change their characteristics as they grow, colonies of social insects also change their behavior and other traits in response to colony size. How individual colony members can “sense” their own colony size is, however, generally unknown. In this talk we show the first explicit mechanism of colony size related behavioral regulation. In colonies of the queenless ponerine ant, Diacamma sp. from Japan, a mated worker (gamergate), which effectively monopolizes reproduction as the functional queen, regularly patrols the nest to inform her presence to other unmated workers and to inhibit their reproduction. Interestingly, she spends more time patrolling as the colony becomes larger. We show a simple feedback mechanism, relying on individual contacts, that regulates this activity shift in response to changing colony size.